Overview

• Landsat observations indicate the glacier lost contact with Prow Knob between July 13 and August 6, 2025.
• The exposed landform is now a roughly 2-square-mile island whose highest point rises just over 1,000 feet.
• Alsek Lake has grown from about 45 to roughly 75 square kilometers since 1984 as surrounding ice has retreated.
• Specialists say islands of this scale revealed by glacier retreat are uncommon in Alaska in recent decades.
• Loss of ice contact increases the likelihood of calving and could alter shorelines, circulation and outburst flood risk, prompting continued monitoring by researchers and park managers.